On Mon, May 21, 2012 at 1:42 PM, Josh Berkus <j...@agliodbs.com> wrote: > >> Earlier you said that this should be an ideal setup for IOS. But it >> isn't really--the ideal set up is one in which the alternative to an >> IOS is a regular index scan which makes many uncached scattered reads >> into the heap. I don't think that that situation can't really be >> engineered with a where-less query. > > Can you give me some suggested comparisons which *would* be ideal, then?
Are you looking for vaguely real-life examples, or highly contrived examples used to dissect the server? For vaguely real life, take your example of pgbench -i -s200 -F 50, and I have 2Gig RAM, which seems to be the same as you do. With select only work load (pgbench -S -M prepared -T 30), I get tps = 193 But now enable index-only scans: psql -c "create index on pgbench_accounts(aid, abalance);" and it goes up to. tps = 10137 Cheers, Jeff -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
